1. Field of the Invention
The present invention relates to a multi-helical ball sleeve structure, and more particularly to a multi-helical ball sleeve structure that can enhance the lifetime and increase the working efficiency.
2. Description of the Related Art
A working machine, such as a punching bed, is used for processing a workpiece. In general, the punching bed is provided with a plurality of ball sleeves to reduce the friction. A conventional ball sleeve 1 in accordance with the prior art shown in FIGS. 1-3 is mounted on the punching bed to reduce the friction of the punching bed during the working process. The conventional ball sleeve 1 is formed with a plurality of through holes 2 for receiving a plurality of balls 3.
However, the conventional ball sleeve 1 has the following disadvantages.
1. The support points of the conventional ball sleeve 1 are not enough, thereby increasing the bearing pressure of the conventional ball sleeve 1.
2. The contact surface is not evenly distributed, and the friction action is concentrated on the same position, so that the conventional ball sleeve 1 is easily worn out during a long-term utilization.
3. When the conventional ball sleeve 1 is broken, the friction coefficient is increased during the sliding movement, thereby increasing the resistance.
4. The conventional ball sleeve 1 is easily worn out, so that the conventional ball sleeve 1 needs to be replaced frequently, thereby decreasing the working efficiency.
5. The conventional ball sleeve 1 is rotatably and movably mounted in a guide sleeve 4. The balls 3 receiving in the through holes 2 of the conventional ball sleeve 1 have the same circumferential height, so that the guide sleeve 4 is easily worn out during a long-term utilization, thereby increasing the gap between the upper die (not shown) and the lower die (not shown) of the mold (not shown), and thereby wearing the mold.